The present invention relates generally to an apparatus and method for performing a thermal therapy patient treatment protocol. More particularly, the invention relates to a novel apparatus and method for physically separating organs to enable aggressive thermal therapy to be administered safely and relatively comfortably, on an outpatient basis, if desired.
Thermal therapy has been proven to be an effective method of treating various human tissues. Thermal therapy includes tissue freezing thermotherapy, hyperthermia treatment and various cooling treatments. Thermotherapy treatment is a relatively new method of treating cancerous, dieseased and/or undesirably enlarged human prostate tissues. Hyperthermia treatment is well known in the art, involving the maintaining of a temperature between about 41.5xc2x0 through 45xc2x0 C. Thermotherapy, on the other hand, usually requires energy application to achieve a temperature above 45xc2x0 C. for the purposes of coagulating the target tissue. Tissue coagulation beneficially changes the density of the tissue. As the tissue shrinks, forms scars and is reabsorbed, the impingement of the enlarged tissues, such as an abnormal prostate, is substantially lessened. Further, tissue coagulation and its beneficial effects are useful for treating cancerous tissue, because cancer cells are particularly susceptible to abnormal temperatures. Cancer cells can be treated in accordance with the present invention with temperatures in excess of 100xc2x0 C. without damage to the therapy applicator or discomfort to the patient.
The higher temperatures required by thermotherapy require delivery of larger amounts of energy to the target prostate tissues. At the same time, it is important to protect nontarget tissues from the high thermotherapy temperatures used in the treatment. Providing safe and effective thermal therapy, therefore, require devices and methods which have further capabilities compared to those which are suitable for hyperthermia.
Although devices and methods for treating prostate cancer and benign prostatic hyperplasia have evolved dramatically in recent years, significant improvements have not occurred and such progress is badly needed. As recently as 1983, medical textbooks recommended surgery for removing cancerous or impinging prostatic tissues and four different surgical techniques were utilized. Suprapubic prostatectomy was a recommended method of removing the prostate tissue through an abdominal wound. Significant blood loss and the concomitant hazards of any major surgical procedure were possible with this approach.
Perineal prostatectomy was an alternatively recommended surgical procedure which involved gland removal through a relatively large incision in the perineum. Infection, incontinence, impotence or rectal injury were more likely with this method than with alternative surgical procedures.
Transurethral resection of the prostate gland has been another recommended method of treating benign prostatic hyperplasia. This method required inserting a rigid tube into the urethra. A loop of wire connected with electrical current was rotated in the tube to remove shavings of the prostate at the bladder orifice. In this way, no incision was needed. However, structures were more frequent and repeat operations were sometimes necessary.
The other recommended surgical technique for treatment of benign prostatic hyperplasia was retropubic prostatectomy. This required a lower abdominal incision through which the prostate gland was removed. Blood loss was more easily controlled with this method, but inflammation of the pubic bone was more likely.
With the above surgical techniques, the medical textbooks noted the vascularity of the hyperplastic prostate gland and the corresponding dangers of substantial blood loss and shock. Careful medical attention was necessary following these medical procedures.
The problems previously described led medical researchers to develop alternative methods for treating prostate cancer and benign prostatic hyperplasia. Researchers began to incorporate heat sources in Foley catheters after discovering that enlarged mammalian tissues responded favorably to increased temperatures. Examples of devices directed to treatment or prostate tissue include U.S. Pat. No. 4,662,383 (Harada), U.S. Pat. No. 4,967,765 (Turner), U.S. Pat. No. 4,662,383 (Sogawa) and German Patent No. DE 2407559 C3(Dreyer). Though these references disclosed structures which embodied improvements over the surgical techniques, significant problems still remained unsolved.
Recent research has indicated that cancerous and/or enlarged prostate glands are most effectively treated with higher temperatures than previously thought. Complete utilization of this discovery has been tempered by difficulties in protecting rectal wall tissues from thermally induced damage. While shielding has been addressed in some hyperthermia prior art devices, the higher energy field intensities associated with thermotherapy necessitate devices and methods having further capabilities beyond those suitable for hyperthermia. For example, the microwave-based devices disclosed in the above-referenced patents have generally produced relatively uniform cylindrical energy fields. Even at the lower energy field intensities encountered in hyperthermia treatment, unacceptably high rectal wall temperatures have limited treatment periods and effectiveness.
In addition, efficient and selective cooling (for heat-based treatments) or warming (for freezing treatment) of the devices is rarely provided. This substantially increases patient discomfort and increases the likelihood of healthy tissue damage during benign prostatic hyperplasia treatments. These problems have necessitated complex and expensive temperature monitoring systems along the urethral wall. Satisfactory ablative prostate cancer therapy using extremely high or low temperature treatments cannot be undertaken without effective thermal control of the therapy device including effective cooling of exterior portions of the therapy device.
It is therefore an object of the invention to provide an improved apparatus and method suitable for thermal therapy treatment of tissue.
It is another object of the invention to provide an improved method and apparatus for physically separating mammalian organs.
It is yet another object of the invention to provide an improved method and apparatus for physically separating human organs for thermal isolation purposes.
It is a further object of the invention to provide an improved apparatus and method for thermal therapy treatment which separates the prostate from the rectum.
It is yet a further object of the invention to provide a novel method and apparatus for thermal therapy treatment that utilizes a fluid to separate the prostate from the rectum for thermal isolation purposes.
It is a still further object of the invention to provide a novel means for dynamic monitoring of the treatment temperature distribution and to use such information to aid in the control of the deposited power level and its distribution.
It is another object of the invention to provide an improved applicator which can be inserted into a space between a prostate and a rectum and be positioned with respect to the prostate and maintained in position during treatment.
It is a further object of the invention to provide improved control of both power level and the distribution of the power deposited in the prostate in a dynamic fashion during thermal therapy which compensates for physiological changes (temperature, blood flow effects) that can occur during therapy and accommodates operator-desired alterations in the therapeutic energy distribution within the prostate.
It is an additional object of the invention to provide an improved thermal therapy device which minimizes energy reaching the rectal wall in benign prostatic hyperplasia or prostate cancer thermotherapy treatment.
Other advantages and features of the invention, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, wherein like elements have like numerals throughout the drawings.